Buttons are commonplace structures for turning on and off various types of devices, or for selecting items or functions in menu type setups. In most instances buttons are associated with electrical equipment and can control a variety of functions depending on the particular arrangement. These button structures generally operate in a simple manner wherein the activation/deactivation function is accomplished by depressing and releasing the button. The button may be directly coupled to an electrical circuit or may be used as an interface to actuate an electronic device.
Electrical or electronic equipment, such as process controllers, deep fryers, and other programmable controllers, utilize interface panels or faceplates generally having a plurality of buttons to allow the user to operate and/or program the device. The depress-and-hold and the-depress-and-release actions on the button cause the controller, for instance, to perform a particular function. The buttons may control a variety of functions and may also be programmable depending on the particular application or device. Programmable process controllers, for instance, have many buttons associated with the front panel in order to program and operate the controller. In some instances, however, it may be necessary to block or restrict the use of a particular button or a group of buttons. In the case of a process controller, while there may be a plurality of buttons, only certain of those buttons may actually be used in the field or used by an operator once the device is installed in a customer application. Also, these buttons may be used prior to use in the field or prior to use in the customer application. It then becomes necessary to prevent the utilization of the button once its use is no longer needed or allowed.
This occurs in original equipment manufacturer (OEM) situations and/or in the post-installation process where single products, such as process controllers, may be programmed to perform a variety of tasks. Once the controller has been installed and/or programmed for the particular application, it may be necessary to restrict or prevent access to some of the buttons. It may certainly be possible to restrict or prevent access to the function of the button by deactivating the same by firmware, software, or the like. However, these methods are too costly or difficult to implement. They also do not allow for easy reactivation or use, should the need arise, without compromising the security of the lockout through software reactivation schemes.
It is thus an object of the present invention to provide a lockable mechanical button structure.
It is another object of the present invention to provide a selectively lockable mechanical button structure especially for use in an interface panel or faceplate associated with an electrical device.
It is a further object of the present invention to provide an interface panel for an electrical device, such as a process controller, having buttons that can be disabled or enabled by making an adjustment of the button.